Urinary System Dieases and Theraputics Flashcards
where are the kidneys located within the body?
dorsal cranial abdomen
which kidney is more cranial in the abdomen of domestic species?
right
where are kidneys located in relation to the peritoneum?
retroperitoneum
what info can be gained through performing an IV urogram /urography?
illustrates the structural integrity of the urinary system and can show if there are any blockages or leaks
what is involved in an IV urogram/urography?
injection of dye that is excreted by the kidneys so it shows movement through the urinary system and can illustrate any issues
what is the nephron?
filtration component of the kidney
what is the glomerulus?
capillary bed within the kidney where glomerular filtrate is formed
what processes occur within the glomerulus?
filtration of blood to form glomerular filtrate
in a healthy kidney are proteins filtered into the Bowman’s capsule by the glomerulus?
no - they remain in the blood
why is there high pressure in the glomerulus?
the capillary bed is in the middle of 2 arteries in series
what occurs in the proximal convoluted tubule of the kidney?
reabsorption of glucose, electrolyte handling (reabsorption or secretion)
what occurs in the loop of Henle?
counter current flow to enable production of concentrated urine, water reabsorption
what occurs in the distal convoluted tubule and collecting duct?
electrolyte and acid base regulation
site of ADH action and water reabsorption (fine tuning of urine conc.)
define azotemia
elevation of urea +/- creatinine in the blood stream
in health what normally happens to urine and creatinine?
excreted through the kidneys
what is uraemia?
clinical signs associated with azotemia (nausea and innappetance)
what are the clinical signs associated with azotemia?
nausea
inappetance
what is polyuria?
excessive urination
what is oliguria?
a small amount/inadequate urine production
what is anuria?
absence of urine production - life threatening
what is polydipsia?
excessive water intake
what is pyelonephritis?
bacterial kidney infection (either uni or bilateral)
what is glomerulonephritis?
inflammation of the glomeruli
what is renal insufficiency?
measurable reduction in kidney function
what is renal disease?
specific, underlying disease of the kidneys which may be acute or chronic
what is acute kidney injury?
sudden onset kidney disease
what is chronic kidney disease?
> 3 months duration of kidney disease
what is the most readily measurable sign of kidney disease?
inability to concentrate urine
what is the name of appropriate / well concentrated urine?
hypersthnuric
define hypersthenuric
appropriate / well concentrated urine
what is the urine specific gravity in dogs of hypersthenuric urine?
> 1.030
what is the urine specific gravity in cats of hypersthenuric urine?
1.035
what is submaximally concentrated urine?
urine where there has been some concentration by the kidney
what is the USG of submaximally concentrated urine in cats?
1.012 - 1.035
what is the USG of submaximally concentrated urine in dogs?
1.012 - 1.030
what is isosthenuria?
no modification of urine concentration - kidneys have done nothing to concentrate urine
what USG suggests isosthenuria in all species?
1.008-1.012
what USG suggests hyposthenuria in all species?
<1.008
what is hyposthenuria?
active dilution of urine, kidneys are actively getting rid of more water than usual
what are the 4 main methods of urine collection?
free catch
non-absorbable cat litter
catheterisation
cystocyntesis
when should a free catch urine sample be taken?
mid flow
what device can be used to aid free catch urine sampling?
uripet
what animals can be catheterised conscious?
male dogs
what animals must be anaesthetised in order to be catheterised?
cats and female dogs
what is the only sterile method of urine collection?
cystocyntesis - use of a needle directly into the bladder
what is the preferred method of urine collection?
cystocyntesis
why are all other methods of urine collection non sterile?
involve some way of bacteria / cell contamination (either from the environment or the animal itself)
catheterisation can lead to contamination with cells from the urethra and vulva/prepuce
what are the 2 methods of performing cystocentesis?
blind by palpation of bladder
ultrasound guided
what are the 5 main areas of urinalysis?
urine specific gravity (USG) dipstick microscopy cytology bacterial culture
what equipment is used to perform USG measurements?
refractometer
what can be analysed reliably on a urine dipstick?
pH glucose ketones protein blood
what can be identified in urine using microscopy?
crystals or casts
what are renal casts?
impression of the insides of renal tubules, formed from a variety of materials, e.g. protein (hyaline), cells (cellular)
what is the aim of bacterial culturing of urine?
to check for presence of bacteria by allowing them to grow
are some crystals found in healthy animals?
yes - struvite are one example
what will urine cytology look at?
cells and bacteria present
what can be identified on blood tests that would indicate urinary system problems?
urea and creatinine
where do urea and creatinine originate from?
endogenous waste products excreted by the kidneys
where does urea originate from?
protein breakdown anywhere in the body
what can falsely raise urea value on a blood test?
recent protein meal
how can falsely elevated urea be avoided?
using fasted samples
where is creatinine derived from?
breakdown of muscle creatinine
what no pathological reason may cause an apparently lowered creatinine level?
poorly muscled animal
what does azotemia indicate?
reduced glomerular filtration of blood
what are the 3 types of azotemia?
pre-renal
renal
post renal
what is pre-renal azotemia due to?
inadequate renal perfusion - kidneys are not filtering enough blood due to reduced flow
what could be a cause of pre-renal azotemia?
hypovolaemia
what is renal azotemia due to?
reduced functional mass of the kidneys due to underlying kidney disease (less blood filtered by kidney)
what is post-renal azotemia due to?
kidneys are functioning but waste products are not excreted
what are the 2 main causes of post renal azotemia?
obstruction of the urinary tract (urethral, ureteral)
rupture of the urinary tract
what can rupture of the urinary tract lead to?
uroabdomen - leads to urine being reabsorbed by peritoneaum
what test must be performed in a azotemic patient?
urinalysis
what is the body’s normal response to pre-renal azotemia?
to preserve as much water as possible and prevent further fluid loss - production of more concentrated urine
what indicates renal azotemia?
with poorly concentrated urine (less than hypersthenuria)
how can post-renal azotemia be diagnosed?
imaging
is it normal to produce dilute urine if non azotemic?
it can be
what are other findings on blood tests often seen alongside azotemia?
hyperphosphataemia
electrolyte derangements
anaemia
why may azotemia be associated with hyperphosphataemia?
reduced renal excretion so phosphate is not being excreted either
what electrolyte derangements are common as a result of kidney disease?
hypo or hyperkalaemia
why is hypokalaemia common in kidney disease?
excessive potassium loss due to kidney damage
what symptoms does hypokalaemia contribute to in dogs/cats with kidney disease?
weakness and inappetance
why can kidney disease lead to anaemia?
EPO (erythropoetin) is synthesised by the kidneys less in disease so fewer RBC are produced
RBC in uraemic patients have a reduced life span
what can radiography of the urinary tract be used to show?
size and shape of kidneys radiopaque stones radiolucent stones evaluation of ureteric course / insertion evaluation of morphology
how can radiolucent stones be shown on radiography?
with double contrast using dye and air
what can urinary tract ultrasound show?
parenchymal detail of kidney and prostate
evaluation of bladder wall morphology
evaluation of some causes of a post-renal azotemia - location of ureteric obstruction and free fluid associated with uroabdomen
why is cytology/biopsy not often used for kidneys?
due to large blood supply and potential for heavy bleeding
how can the risk of heavy bleeding following a kidney biopsy be avoided?
check animals clotting
samples taken from cortex only
what may a kidney biopsy be used to diagnose?
renal lymphoma (via FNA) glomerular disease (trucut biopsy)
how are kidney biopsies performed?
percutaneous - ultrasound guided
what is cytology / biopsy commonly used for in the prostate?
prostatic wash
suction biopsy
what is cystoscopy used for?
direct visualisation of lower urinary tract
collection of guided biopsy samples
laser lithotripsy of stones
what is acute kidney injury?
acute nephron damage / dysfunction
how do symptoms present during AKI?
very quickly, animal becomes profoundly ill due to sudden accumulation of toxins
what is chronic kidney disease?
chronic nephron loss
how do symptoms present during chronic kidney disease?
more gradual onset due to gradual decline in renal function
why are kidneys highly susceptible to toxic / ischaemic injury?
receive / require 20% of cardiac output despite being only 0.5% of body weight due to being hugely metabolically active so will be damaged by any reduction in blood flow/volume. They also produce many waste products which are toxic if not cleared
what urine output is AKI most commonly associated with?
anuria /oliguria - kidneys suddenly stop working
what urine output is AKI less commonly associated with?
polyuria
why is AKI with polyuria easy to manage?
toxins are still being removed so less damage is occuring
what are the main causes of intrinsic AKI?
toxic
ischaemic
infectious
cutaneous and renal glomerular vasculopathy (CRGV) in dogs
what can cause AKI due to toxins in dogs?
raisins/ grapes
NSAIDs - particularly human
diuretics - lead to hypovolaemia
cholecalciferol - leave mineral deposits in kidneys
what can cause AKI due to toxins in cats?
lilies ethylene glycol NSAIDs - particularly human diuretics - lead to hypovolaemia cholecalciferol - leave mineral deposits in kidneys
why do NSAIDs cause AKI?
inhibition of prostaglandins which have a role in control of renal plasma flow
what are the infectious causes of AKI?
leptospirosis (dogs)
pyelonephritis
what is AKI caused by cutaneous and renal glomerular vasculopathy (CRGV) in dogs accompanied by?
skin lesions
what is cutaneous and renal glomerular vasculopathy (CRGV) also known as?
alabama rot
what are the clinical findings of AKI?
azotemia, uraemia
hyperkalaemia (in anuric or oliguric patients)
hyper or hypoperfusion
other signs relating to intoxication
what are the signs of azotemia (uraemia)?
lethargic
depressed
inappetant
nauseous
why can cases of AKI with an/oliguria develop hyperkalaemia?
potassium is not being excreted so will build up
what can hyperkalaemia lead to?
cardiac arrhythmias / arrest
when may a patient with AKI become hyperperfused?
an/oliguria so fluid is not being lost and volume overload can occur
when may a patient with AKI become hypoperfused?
polyuric - lots of fluid loss
what signs are associated with ethylene glycol toxicity?
hypocalcaemia
tremors
why does ethylene glycol toxicity result in hypocalcaemia?
production of calcium oxalate crystals causes excessive calcium use
what additional signs may be seen with leptospirosis?
icterus - indicating liver damage
how can AKI be diagnosed through blood tests?
short clinical illness
acute azotemia with increased urea, creatinine, phosphate and K+ (if an/oliguric)
reduced K+ if polyuric
with inappropriately concentrated urine
no evidence of urinary tract obstruction or rupture
how can you tell that azotemia due to AKI is not pre - renal?
will be accompanied by inappropriately concentrated urine
how can you tell that azotemia due to AKI is not post - renal?
no evidence of urinary tract obstruction / rupture
what are the urinalysis findings associated with AKI?
submaximally concentrated urine - often isosthenuric
casts are commonly seen indicating tubular injury
calcium oxalate monohydrate crystals will indicate ethylene glycol toxicity
inflammatory cells or positive bacterial culture indicating pyelonephritis
what is indicated by the presence of casts in urine?
tubular injury
what is indicated by the presence of calcium oxalate monohydrate crystals in urine?
ethylene glycol toxicity
what is indicated by the presence of inflammatory cells or a positive bacterial culture in urine?
pyelonephritis
what type of calcium crystals are seen in healthy animals?
calcium oxalate dihydrate
how should urine output be monitored?
catheterisation ideally but can use pads and weigh (1g=1ml of urine)
what does monitoring of urine output show?
differentiation between an/oliguria and polyuria
what are the main steps involved in AKI management?
remove underlying cause
supportive management, pending renal recovery
specific treatment if available
how can removal of underlying cause of AKI be achieved?
stop known nephrotoxic drugs (even if prescribed)
proceed with gastric decontamination / absorption of substance ingested (if applicable) to prevent further uptake by the body
what is involved in the supportive management of AKI?
manage fluid balance, electrolytes, renal toxins - encouraging urination and removal of toxins
supplementary management including nutrition, nausea and pain
how can nausea be managed?
anti-emetics
what analgesia may be given to patients with AKI?
opioids NOT NSAIDs
what fluid type should be initially used in patients with AKI?
crystalliods - Hartmann’s
what should be treated first when giving IVFT to an AKI patient?
correct any hypovolaemia (pre-renal)
what IVFT bolus should be given to cats to correct hypovolaemia?
5ml/kg over 10-15 mins
what is euvolaemia?
normal circulatory or blood fluid volume in the body
once an AKI patient is euvolaemic what should be corrected?
any dehydration
how should dehydration be corrected in the euvolaemic patient?
replace over 6 hours
if an animal with AKI appears clinically euhydrated what % dehydration should be assumed?
5%
when should IVFT not be given to a patient with AKI?
if overhydrated as can lead to volume overload
what level of blood K+ is classed as hyperkalaemia?
> 6.5-7 mmol/l
what can hyperkalaemia lead to?
cardia arrhythmias and/or standstill
why may AKI lead to hyperkalaemia?
kidneys are major route of body K+ excretion
an/oliguria can cause build up of K+
describe features of an ECG of a patient with hyperkalaemia
flattened P
wide QRS
spiked T
what heart rate may hyperkalaemic patients have?
bradycardia
what is involved in the ongoing treatment of AKI?
fluid therapy
treatment of hyperkalaemia
specific therapy for cause (if available)
what is the role of IVFT in ongoing treatment of AKI?
maintain hydration and euvolaemia
replacement of ‘outs’
how is hyperkalaemia treated?
crystalliod IVFT to ensure renal perfusion
calcium gluconate
glucose
insulin
what is the role of calcium gluconate in the treatment of hyperkalaemia?
stabilises the myocardiocytes to make them less prone to arrhythmias
why are glucose and insulin administered to hyperkalaemic patients?
glucose stimulates insulin release which will stimulate uptake of glucose and potassium alongside - reduces K+ within blood
what is the specific therapy for ethylene glycol toxicity?
ethanol to reverse crystal formation
what is the specific therapy for Leptospirosis and pyelonephritis?
antibiotics
what are the key areas of nursing care for the patient with AKI?
ensure euhydrated, avoid overhydration ensure renal prefusion manage inappetance and nausea analgesia provide nutrition
how can hydration levels be monitored?
weigh patient to ensure body weight is maintained
what value should systolic BP be to ensure adequate renal perfusion?
120-150 mmHg
what is the minimum value of systolic BP to ensure adequate renal perfusion?
> 80mmHg
how can inappetance and nausea be managed?
maropitant - anti emetic
how may nutrition be provided to AKI patients?
orally or assisted
what must be done if feeding liquid food to a patient on IVFT?
it should be incorporated into fluid therapy calculation
what should be done if kidneys fail to respond to initial supportive therapies?
trial diuretic to stimulate urination
what does of diuretic should be given to see if patient can be encouraged to urinate?
2mg/ml frusemide ONCE
what is indicated by persistent anuria (+/- volume overload and +/- unmanageable hyperkalaemia)?
renal replacement (dialysis) or euthanasia
what clinical findings in an AKI patient would indicate dialysis or euthanasia?
persistent anuria -
+/- volume overload and +/- unmanageable hyperkalaemia
what is the survival rate for AKI in dogs?
34-59%
what is the survival rate for AKI in cats?
27-42%
why do patients presenting with polyuria alongside AKI have a better prognosis than those presenting with an/oliguria?
they are able to flush toxins from their body and so there is less damage
what do ~50% of AKI sufferers have long term?
CKD - chronic kidney damage
what is the most common kidney disease in cats and dogs?
chronic kidney disease
in what species is chronic kidney disease the most common?
cats
in what age group is CKD most commonly diagnosed?
older patients
define chronic kidney disease
functional and/or structural kidney disease of >3 months duration
can CKD be reversed?
no - irreversible and progressive
is the onset of CKD acute or gradual?
gradual
what is the management of CKD aimed at?
protecting remaining nephrons and managing clinical consequences
what is the aim of protecting the remaining nephrons of animals with CKD?
reducing progression of the disease
what are the 6 main causes of CKD?
chronic interstitial nephritis glomerulonephropathy undiagnosed / untreated infections chronic obstructive disease congenital issues neoplastic
what causes chronic interstitial nephritis?
often unknown, it is the end of many pathological processes
what is chronic interstitial nephritis?
chronic inflammation within the kidney
what congenital diseases can lead to CKD?
poly-cystic kidney disease and renal displasia (dogs - cysts replace functional renal tissue)
what are the findings within an animals history that will suggest CKD?
subtle or non-specific initially in some patients PUPD weight loss lethargy weakness inappetance
what GI signs may be seen in an animal with CKD?
vomiting diarrhoea haematemesis melaena constipation second to dehydration in cats
what signs associated with hypertension may be seen in an animal with CKD?
blindness
neurological
what findings on a clinical exam suggest CKD?
catabolic state - reduced body (muscle) condition typically dehydrated weakness uraemic ulcers/ uraemic halitosis hypertensive retinopathy
why are patients with CKD typically dehydrated?
uncontrolled polyuria - kidneys are unable to concentrate urine
may also be v+/d+
what causes weakness in the patient with CKD?
polyuria and associated excretion of K+
what can excessive loss of K+ in the CKD patient lead to?
neck ventroflexion
hypokalaemic myopathy
what causes uraemic ulcers and uraemic halitosis?
increased urea present in saliva - this is converted to ammonia by bacteria in the mouth
what will kidneys feel like on palpation in a patient with CKD?
small and irregular
what is rubber jaw?
soft bone of jaw seen in young animals with CKD
what are the target organs of hypertension?
eyes (ocular)
renal
cardiac
neurological
what is hypertensive retinopathy?
renal oedema and hemorrhages due to the effects of hypertension on the capillaries there
what can hypertensive retinopathy lead to?
acute blindness
what are target organs?
organs within the body that are particularly susceptible to damage in the small blood vessels within them due to hypertension
How can CKD lead to worsening kidney function due to its hypertensive effects?
kidney disease causes increased blood pressure which in turn damages kidneys causing further BP increase
what is an additional complication of systemic hypertension outside of the target organs?
epistaxis
what is considered normal systolic blood pressure?
120-140 mmHg
what is normal systolic BP for sighthounds/deerhounds in hospital settings?
10-20 mmHg higher than others
why do sighthounds/deerhounds have a recognised higher systolic BP than other animals?
clear predisposition to in-hospital situational hypertension
what would a systolic BP of <140mmHg be described as?
normotensive
what systolic BP is considered hypertensive?
160-179 mmHg
what is the risk of organ damage once the systolic BP is deemed hypertensive?
moderate
at what point is treatment for hypertension warranted?
> 160 mmHg
what is the ideal method of BP measurement?
direct arterial line
how many blood pressure readings hsould be taken?
5-7 consistent readings
what blood pressure readings should be discounted?
first reading and those before the plateau of meaurement
when should a second set of blood pressure readings be taken?
2 hours later
what is the correct BP cuff width if using indirect measuring techniques?
30-40% circumference of limb/tail
what must be demonstrated to diagnose CKD?
renal azotemia
what is diagnostic for CKD?
inappropriately concentrated urine
with azotemia
what is the name of the new blood test used for diagnosis of CKD?
symmetric dimethylarginine (SDMA)
how does the SDMA blood test for CKD work?
approximated GFR
what other laboratory findings may be seen alongside azotemia in a CKD patient?
anaemia
increased phosphate
reduced K+
what blood pressure findings would suggest CKD?
hypertension
why may imaging be performed in a CKD patient?
to rule out any other cause of issues that may be treatable/ require different treatment
what is involved in the initial management of CKD cases?
discontinue nephrotoxic drugs
find and treat any underlying correctable cause
correct and maintain fluid balance
what may be an underlying correctable cause of CKD?
hypertension
urinary tract infection (pyelonephritis)
ureteroliths
how can fluid balance of a CKD patient be managed?
encourage oral intake of water
give wet/soaked food
SQ fluids (owner or vet administered)
oesophageal tube
how can oral water intake be encouraged?
different water stations in different places
different types of bowls
ensure water in bowl is high enough so cat doesn’t have to move eyes below level of bowl to drink
how can progression of CKD be delayed?
renal diet - improves survival
control - hypertension, proteinuria, hyperphosphataemia and hyperkalaemia
avoid further kidney insult
how can further kidney insult be avoided?
prevention of secondary infections
careful/no use of NSAIDs
what is the aim of a renal diet?
maximise quality/longevity of life
limit clinical manifestations of disease
slow progression
how should cats eating/weight be managed to ensure they are receiving proper nutrition to manage CKD?
calculate and feed RER
weigh food eaten and any left to calculate deficit to animals intake
monitor bodyweight and condition (BCS and weighing)
adjust intake based on any changes
what must be avoided in a renal diet?
protein calorie malnutrition - ensure animal eats sufficient calories
avoid food aversion